This invention relates to a deployable bridge composed of a plurality of identical bridge sections each having two identical lateral track elements and each being provided with a roadway carrier and a bottom boom (chord) that is connected with the roadway carrier by means of adjustment elements. The bottom boom is adjustable in height with respect to the roadway carrier and constitutes a bottom tensioning assembly. The track elements of each bridge section are connected with one another by transverse supports and the roadway carriers and the bottom booms of bridge sections that are arranged one behind the other can be coupled together. The invention also relates to a vehicle equipped with a telescoping carrier for laying the bridge.
Deployable bridges are employed for allowing vehicles weighing up to about 70 tons to traverse obstacles such as bodies of water, depressions in the terrain and the like. While the majority of the obstacles lie in a range of about 14 m, the vehicles should also be able to traverse obstacles of 40 to 45 m. It is known to assemble for this purpose deployable bridges from a different number of bridge sections depending on the desired bridge length. It is of advantage to selectively use identical bridge sections as end or ramp sections or as center or intermediate sections.
A bridge of the above-outlined type is disclosed in German Offenlegungsschrift 38 14 502 to which corresponds U.S. Pat. No. 5,042,101. The bottom booms of the bridge elements disclosed therein are arranged in a straight line one behind the other and the roadway carriers constituting the track form an upwardly oriented polygon. Since the roadway carriers have a uniform length, the bottom booms and the cross-struts that connect the bottom booms with the roadway carriers must be varied in length depending on the position of the bridge element within the bridge before they can be finally locked and coupled together. Such an arrangement, however, has the drawback that a considerable amount of time is required for the installation of the entire bridge. Moreover, this known bridge has the drawback that its structural height is considerable if the bridge is long so that the vehicles must traverse a "mountain" which greatly reduces the crossing performance.
German Offenlegungsschrift 28 07 859 discloses a bridge that is composed of individual elements. In this structure, however, non-identical bridge elements (ramp sections and center or intermediate units) are provided and a separate bottom tensioning assembly with a reinforcing chain and mechanically adjustable pillars are used. The unlike elements (ramps and end sections as well as intermediate and middle sections) involve increased transporting expenses compared to identical bridge elements. Moreover, the number of bridges that can be built from these bridge elements is limited to the number of available ramp sections.
German Patent 1,207,948 discloses a deployable bridge composed of sections (ramp sections and center sections) each having two pairs of juxtaposed bridge elements. Each bridge element includes a roadway carrier forming the track and a bottom boom, all connected with the roadway carrier by pillars that are disposed at the beginning and at the end of the bridge elements. The pillars which are subjected to pressure have a joint in the center to render them collapsible and the bottom boom can be folded against the roadway carriers. This results in a lower transporting height for the bridge elements as compared to the height of the finished bridge structure. The corner points of the bridge carriers are provided with diagonally arranged tension elements which impart additional stability to the bridge carrier and to the bridge section. The assembly of the bridge is performed individually for each bridge element which involves a considerable installation time. The bridge sections for the ramps and the major portion of the bridge are unlike structures.